Automobile securement mechanism to freight car

ABSTRACT

Automobiles are lifted from alongside a fully enclosed multi-level deck rail car and loaded onto the decks through a side opening of the rail car. The automobiles are pushed forwardly from the rear towards an end of the rail car. Detachable securement means on the decks and the frames of the cars cooperate automatically in response to forward movement of the automobiles to compress the spring suspension systems of the automobiles and lock the automobiles to the decks to prevent longitudinal or sideward movement of the automobiles on the decks during transport.

This is a division of Ser. No. 646,940, filed Jan. 6, 1976, now U.S.Pat. No. 4,067,469, issued Jan. 10, 1978.

BACKGROUND OF THE INVENTION

This invention relates to loading and unloading of automobiles into andfrom rail cars, particularly rail cars of the multiple-level deckdesign.

At present, the conventional manner of loading automobiles intomulti-level deck rail cars is the "circus" method. A number of railcars, connected end-to-end and provided with open ends, or end doors,are positioned at the loading area. Bridge plates are placed on andbetween same-level decks of adjacent rail cars so that the automobilesmay be driven from rail car to rail car and a ramp is installed fromground level to the proper deck level of the end rail car. A squad ofdrivers then drive the automobiles from a marshalling area to theloading area, up the ramp and through the bridged rail cars until theycome to the last automobile which has been loaded. The automobiles areparked in the rail cars and tied down in place by ratchets and chains.As each level becomes full, the end ramp is moved and positioned at anew level and the process is repeated. In essence, the presently usedmethod is the same as filling cars into a long narrow tunnel.

One of the main desires in automobile shipment is to have the rail carspace used as efficiently as possible, with the maximum number ofautomobiles being put into each rail car. Circus loading does provide ahigh degree of space utilization.

However, the present circus method of end loading rail cars has manydisadvantages. Much time is required to position the bridge plates andinstall the end ramps. The necessary slope of the end ramps and theoccasional slope of bridge plates between rail cars having decks ofunequal height often causes damage to the mufflers or undercarriage ofthe automobiles as they are being loaded or unloaded, particularly ifthe driver does not try to avoid jouncing as he drives on the ramp andbridge plates.

If a long train is being loaded, considerable time will be requiredafter each automobile has been loaded for the driver to walk back to themarshalling area to get his next automobile. Additionally, the loadingpersonnel will be widely dispersed, making personnel supervisiondifficult.

Because the automobiles are driven on and off, the operation of theautomobile engines during loading and unloading causes exhaust fumes toaccumulate in the rail cars. This in turn increases the discomfort tothe drivers and the chain installers working in the rail cars. If abattery is dead or a tire has become flat during shipment, unloading isdelayed.

There is little space between the sides of the automobiles and the sidesof the rail cars. As a consequence, it is easy to damage the automobiledoors as the driver gets in or out. The lack of space makes it difficultfor the interior workman to install the necessary tie-down chains, andthe workman is apt to scratch the paint on an automobile with his toolsas he squeezes by the side thereof.

Pilfering and vandalism of automobiles during shipment is an increasingconcern. It is a simple matter to provide a full side covering toend-loaded rail cars, but serious difficulties have been experienced indesigning practical and trouble-free bi-fold or tri-fold end doors whichwill allow end loading and which will completely enclose the ends of therail car during transit.

The main objective of the present invention is to achieve the spaceutilization efficiency of circus loading, while avoiding thedisadvantage mentioned above. In particular, the objects of theinvention are three-fold:

(1) To provide maximum protection and eliminate the possibility ofdamage from pilferage, theft and vandalism during transit;

(2) To minimize manpower requirements, especially the necessity fordrivers to get in and out of automobiles during loading and unloadingoperations;

(3) To reduce as far as possible damage to the automobiles duringloading and unloading.

SUMMARY OF THE INVENTION

In general, the objective of the present invention is met by sideloading of automobiles into a rail car having a side door opening tomultiple-level decks. The rail car is thus essentially a boxcar andpresents no special design problems of providing a structurally soundfully enclosed shell with trouble-free doors.

Automobiles are brought to the side of the rail car, either serially, aswith circus loading, or accumulated at each rail car for batch loading.A modified forklift is used to lift the automobile to appropriate deckheight, insert it through the open doorway and place it on the deck. Aworkman with a self-propelled air-jack immediately moves the automobileto the desired place in the rail car.

Automatically operating securement means are used, comprising hookattachments on the automobile and sockets fixed to the deck floor whichoperate to lock the automobile to the deck automatically when theautomobile has been moved to its desired position.

The workman in the rail car never gets in or out of the automobile.Instead, the workman is positioned at all times between the end of theautomobiles and the rail car door and never has to squeeze by the sidesof the automobiles in the car.

Unloading operations are carried out using a reverse procedure.

Other objects and advantages of the present invention will be set forthin the following detailed description.

BRIEF DESCRIPTION OF THE DRAWING

In the drawings, forming a part of this application, and in which likeparts are designated by like reference numerals throughout the same,

FIG. 1 is a perspective view of a rail car being side-loaded inaccordance with the invention;

FIG. 2 is a plan view of one of the decks of the rail car of FIG. 1;

FIG. 3 is a view similar to FIG. 2 during side-loading operations;

FIG. 4 is a front elevational view of the modified forklift truck usedin the present invention;

FIG. 5 is a side elevational view of the self-propelled air-jack used inthe present invention;

FIG. 6 is an end elevational view of the air-jack of FIG. 5;

FIG. 7 is an elevational sectional view illustrating the automobilesecurement means of the present invention;

FIG. 8 is a sectional view taken generally on line 8--8 of FIG. 7showing the automobile hook attachment nearing its securement socket,with portions broken away;

FIG. 9 is a view similar to FIG. 8, showing the hook partially insertedinto the socket;

FIG. 10 is a view similar to FIG. 8, showing the hook fully insertedinto the socket;

FIG. 11 is a sectional view, taken on line 11--11 of FIG. 10;

FIG. 12 is an end elevational view of a modified socket designed forflush-mounted runners;

FIG. 13 is a plan view showing the securement sockets, the unlocking barand the air-jack;

FIG. 14 is an end view of the unlocking bar, as seen from line 14--14 ofFIG. 13;

FIG. 15 is a sectional view, taken on line 15--15 of FIG. 13, showingthe initial step of unlocking the securement socket;

FIG. 16 is a view, similar to FIG. 15, showing the securement socketunlocked by the unlocking bar.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIG. 1, the side loading concept of the presentinvention involves a standard 89-foot length rail car 10, preferably ofthe flat deck design, although a low-level design can be adapted to thissystem. The rail car superstructure is completely enclosed by ends 11,sides 12 and roof 13 except for double sliding doors 14 on each side ofthe car which provide a 23-foot clear door opening, exposing the threedecks 15, 16 and 17 of the car. The location of the side doors is suchthat the mixture of automobiles, depending on size and spacing, isoptimized. The car superstructure provides three decks with normalheight required in tri-level automobile service. The decks are flat forstandard car deck height. If low-level design is used, angle ramps willbe required at each end of the lower deck 17 to clear the draft gearhousing on the undercarriage of the rail car.

Each deck is provided, as in FIGS. 2, 6 and 7, with center guide rails18 which extend longitudinally of the rail car. Gaps in the center guiderail system are provided at either end of the guide rail adjacent thedoors 14 to provide room for the rail-guided self-propelled air-jack 19to be turned around. Each deck is also provided with runners 20 parallelto and on each side of the center guide rail, the runners having keyshaped slotted holes 21 (FIG. 10) along the length of the upper face 22thereof for attachment of the securement sockets 23 to the runners.Although the runners are shown in most of the drawings as being invertedU-shaped channels with the upper face 22 spaced above the level of thedeck, the runners could be flush-mounted in the deck with the upperrunner face 22 being level with the deck so that the deck surface wouldbe unobstructed, as in FIG. 12.

The securement sockets 23 comprise an elongated body having top andbottom walls 26 and 27 and side walls 28 and open at both ends. The topwall 26 is notched from one end to provide guide surfaces 29 whichconverge inwardly and then extend longitudinally at 29a to stop surface30. Top wall 26 has a horizontal bearing surface 26a on the undersidethereof which extends from the lower edge surface 30a of stop surface30. A transverse shaft 31 extends across the interior of the socketclose to the bottom wall 27 at the guide end of the socket, the shaft 31extending through the side walls and having counterweight lever arms 32fixed thereto. The lever arms each have a laterally extending horizontalstub 34 fixed thereto, the stub extending away from the center of thesocket and being spaced from the free end of lever arm 32 so that whenthe lever arm engages the deck (FIG. 8) the stub 34 will be spaced abovethe deck. A locking plate 35 is fixed along one edge to shaft rod 31inside the socket for swinging movement of the plate about the axis ofshaft 31. The weights of the counterweight lever arms 32 and stubs 34are related to the weight of the locking plate so that the locking platesystem will rotate by gravity to the position illustrated in FIG. 8wherein the lever arms engage the deck and the locking plate has itsmaximum upward inclination.

Socket 23 has a Tee-shaped fastener 36 fixed to the bottom thereof, thehead 37 of which is spaced below the bottom wall 27 and sized relativeto slots 21 in runner 20 so that the head may be passed through the slotwhen the socket is crosswise to the runner but not when the socket isparallel to the runner. A U-shaped retainer member 38 is mounted in tube39 fixed to one end of the socket, the retainer member being rotatablein the tube so that the retainer member legs 40 can be moved between thedotted- and full-line positions of FIG. 8. When in the full-lineposition the retainer member legs 40 will engage the sides of the runner20 so that the socket 23 will be held against rotation about the axis ofTee fastener 36 when the socket is secured to the runner.

FIG. 12 shows a modified socket 23' designed for use with a runner 20'which has its upper surface flush with deck 16. Socket 23' has higherside walls 28 which rest on the deck and support the locking platemechanism at the same height as previously described. A Tee-fastenerhead 37 secure the socket to the runner 20' as before. A retractable pin41 on the front end of the socket passes through a hole in runner 20' toprevent rotation of the socket relative to runner 20' when installed.

Sockets 23 cooperate with hook members 45 mounted underneath theautomobiles 46. Hook members 45 comprise a forwardly extending prong 47having front edge surface 47a, and an upwardly and rearwardly inclinedcam surface 48 on the front end of the prong leading from the front edgesurface 47a to a horizontal bearing surface 49 which extends rearwardlyto shank 50. Shank 50 has a thickness slightly less than the distancebetween guide surfaces 29a of the socket 23 so that it will fittherebetween and will be held thereby against sidewards movement. Theupper end of shank 50 has a laterally extending bearing surface 50a anda Tee-shaped fastener thereon, the head 51 of which is adapted to passthrough an elongated slotted hole 52 in the frame 53 of the automobile46, when the prong is parallel to the length of the slotted hole slotbut not when the prong is crosswise thereto. The slotted holes 52 arepreferably formed during the manufacture of the automobile and thelocation of the slotted hole will depend on the design of theautomobile. For full frame vehicles, these holes could be located in thebottom of the frame at the "hard point" ahead of the rear wheels. Inautomobiles with steel frames, the slotted holes would be in the bottomof the stub frame near the end of the frame section. On automobiles withfloor pans, the slotted holes would be provided at the most suitablelocation. In any event, each automobile would be provided with a pair ofthese slotted holes at opposed locations and on each side of and equallyspaced from the longitudinal centerline of the automobile.

The automobiles will each have a similar slotted hole 54 (FIG. 7)through the frame 53 on the longitudinal centerline of the automobilenear the front end thereof, for reception of the head of the Tee-shapedfastener 55 on the upper end of guide member 56 which depends therefrom.When the guide member is installed and rotated to locked position, thechannel 57 through the lower end of the guide member will be alignedwith the longitudinal centerline of the automobile for reception ofguide rail 18 thereinto. Channel 57 is preferably formed with inwardlyand rearwardly converging guide surfaces 58 to aid in guiding thechannel 57 onto guide rail 18. Although FIG. 7 may tend to indicate thathook members 45 are located on the automobile at the same distance fromthe front of the automobile as guide member 56. However, hook members 45are generally spaced substantially rearwardly of guide member 56.

The self-propelled air-jack 19, illustrated in FIGS. 5, 6 and 13,comprises a body 60 mounted on wheels 61 the rear ones of which areswivel-mounted for steering purposes. A vertically movable jack pad 62is carried by the jack, the jack pad being shaped to engage the rearaxle of an automobile centrally thereof and having an upwardly extendingflange 62a adapted to engage the axle. Column 63 extends upwardly fromthe rear end of the extension arm 64, column 63 being provided at itsupper end with steering handles 65 and valve knobs 66 and 67. Guideplates 68 are fixed to column 63 to form a channel into which guide rail18 is received to prevent sidewards movement of the jack when guideplates 68 are on either side of the guide rail. Jack body 60 containsconventional air-pressure-actuated motors supplied through hose 69 froma suitable source of compressed air (not shown) for actuation of jackpad 62 by manipulation of valve knob 66 and for the driving of wheels 61upon manipulation of valve knob 67. Jack body 60 has a longitudinalchannel 70 in the bottom thereof for reception of guide rail 18thereinto. Column 63 is spaced sufficiently rearwardly of jack pad 62 sothe jack pad flange 62a engages the rear axle of the automobile andpositions the jack pad 62 below the axle before the column 63 reachesthe rear bumper of the automobile.

In loading operations, the automobiles 46 are driven in the usual mannerfrom the marshalling area to a designated location at the side of therail car 10 into which they are to be loaded. The drivers may then driveanother batch of automobiles from the marshalling area to another railcar, or be released for other work assignments.

Three workmen will be used in loading the rail car--a workman inside therail car, an operator for the forklift truck 80 and a driver to drivethe automobiles at the rail car location. As the automobiles are beingbrought to the rail car, the inside workman and the air-jack 19 arelifted up to the first deck of the rail car to be filled and theair-jack is connected to a suitable outlet from the train's pneumaticsystem or from wayside air. A suitable number of securement sockets 23will have been left in the rail car from the last shipment ofautomobiles and the workman will install two of these sockets on runners20 at each end of the rail car. No tools are required for suchinstallation. The workman will also move the air-jack 19 towards an endof the rail car and out of the way of the door opening.

The outside driver will spot the first automobile in front of the dooropening, turn off the engine and set the parking brake. The forkliftoperator then maneuvers the forklift truck so that one of the sets ofextended tines 81 and 82 are disposed on opposite sides of one of thesets of tires 83 of the automobile and the other set of tines 84 and 85are similarly disposed relative to the other tires of the automobile.Tines 81 and 82, and also tines 84 and 85, are brought together (bysuitable control mechanism not shown) so that the tines engage the frontand rear of each of the tires below the axis thereof (FIG. 4). Theforklift truck is then operated to lift the automobile and insert itthrough the rail car door (FIG. 1) and lower it onto the car deck. Theinside workman assists in guiding the automobile so that the centerguide 56 on the automobile will be positioned on center guide rail 18.

The hook members 45 and center guide member 56 may either have beeninstalled on the automobile at the marshalling area, or the driver atthe rail car may install them when the automobiles have been lifted upby the forklift truck.

After the automobile has been lowered onto the deck and the forklifttines have been spread and removed, the inside workman moves theair-jack under the rear of the automobile and hoists the rear axlesufficiently so that the locked rear wheels are raised slightly abovethe deck. The air-jack is then propelled forwardly to move theautomobile towards the end of the rail car which the automobile faces,the automobile and air-jack being guided and held against sidewardsmovement by central rail 18. As the automobile approaches its finalstorage position, the prongs 47 approach sockets 23 as illustrated inFIG. 8. The hook members 45 are designed so that for an automobilehaving an unloaded clearance h between the deck and frame 53, the upperhorizontal surface 49 is spaced above the deck by an amount greater thanthe height of the underside of the top wall 26 of the socket 23.Typically this difference in height may be on the order of an inch and ahalf.

As the automobile continues to move forwardly, prong 47 will insertitself into socket 23. The interengagement of the prong surface 47a andthe surface 35a on the locking plate 35 will then cause the lockingplate 35 to swing downwardly as insertion of the prong into the socketcontinues. The prong then moves forwardly until the inclined cam surface48 thereof engages the lower edge surface 30a of stop surface 30 of thesocket (FIG. 9). The interengaged prong and socket surfaces, 58 and 30a,will cam the prong and frame 43 downwardly as the prong continues tomove forwardly, so that the spring suspension of the automobile,represented schematically at 90 in FIG. 7, is compressed. Thecompression of the spring suspension will increase until the horizontalbearing surface 59 of the prong reaches socket surface 30a. Continualforward movement of the prong then causes the horizontal bearing surface59 to slide under the top wall 26 of the socket and along socket surface26a until the vertical forward surface 50b of the prong and the verticalstop surface 30 of the socket interengage to arrest forward movement ofthe prong and the automobile. By this time the rear surface 50c of theprong will have cleared locking plate 35 so that it is free to pivotback upwardly to the position shown in FIG. 10 wherein theinterengagement of the prong and lock member surfaces 50c and 35b willnow block removal of the prong from the socket. The inside workman thenlowers jack pad 62 and moves the air-jack back to the rail car door inreadiness for the next automobile.

Thus, in response to forward movement of the automobile, by the workmanand air-jack operating at the rear of the automobile, the securementsystem will stop the automobile at the desired point and automaticallylock it in place. The socket and lock plate, together with theautomobile wheels which have been set by the hand brake prior toloading, will hold the automobile against forward or rearward movementduring transit. The interengaging vertical side surfaces 50d of shank 50and the socket member surface 29a, as well as center guide member 46will hold the automobile against sideward movement. The interengagedprong and socket surfaces 49 and 26a will hold the spring suspensionsystem of the automobile in compression to prevent up-and-down movementof the automobile during transit.

While the inside workman is awaiting the next automobile he installs thenext set of sockets 23 to runners 20 at the proper place to provide asmall clearance between automobiles. During the time the inside workmanis moving an automobile into position, removing the jack and installingthe next sockets, the next automobile will have been spotted into placeby the outside driver and picked up by the forklift truck.

As will be noted in FIG. 3, automobiles on opposite sides of the sidedoor opening face in opposite directions, toward the ends of the railcar. This will require the automobile to be spotted outside the rail carso they are headed in the proper direction. Also, when the direction ofthe next-to-be-loaded automobile changes, the inside workman will runthe air-jack to a gap in the central rail system to disengage theair-jack from the central rail so that it may be turned around and thenbe moved to position it at the rear of the next automobile.

Loading operations will continue as above until the next-to-lastautomobile has been loaded onto the deck. The inside workman andair-jack are then removed and moved to the next deck to be loaded. Thelast automobile on the deck is inserted through the open door and setdown on the deck with the prongs 47 close to and in alignment with thesockets 23 which have been installed therefor. The lift truck ismanipulated so that the tines move in unison to move the automobileforwardly so that the prongs enter the sockets 23 and are lockedthereinto. The forklift tines are spread and removed.

The remaining decks are loaded in the same manner as above described.After the rail car has been fully loaded, the doors are closed andlocked to prevent any unauthorized entry into the rail car. The threeworkmen then proceed to the next rail car to be loaded.

The unloading operations are essentially the reverse of the loadingoperations. The rail car doors are opened and a workman reaches insideand under the automobile by the doorway to release the locking lever 32.The forklift truck is manipulated to grip the tires and shift theautomobile rearwardly, to remove the prongs 47 from the sockets, afterwhich the automobile is picked up by the forklift trucks, removed fromthe rail car and set on the ground to be driven away by the driver.

The inside workman and air-jack are then put into the rail car, togetherwith the unlocking tool 100. The unlocking tool 100, illustrated inFIGS. 12-15, comprises an elongated channel-shaped body 101 having adownwardly facing channel 102 adapted to fit down over center guide rail18 and a laterally extending head 103 at one end to whichforwardly-projecting rods 104 are secured. A wedge member 105 having atubular socket 106 is telescoped onto each rod 104 and is biased awayfrom head 104 by spring 107. Each wedge member 105 has an upwardly andrearwardly inclined cam surface 108 and a horizontal surface 109extending rearwardly from the cam surface. The body 101 is provided witha laterally extending tail 110 at its other end for engagement by thefront end of air-jack 19.

The inside workman places the unlocking tool 100 on the guide rail 18 atthe rear of the automobile to be unlocked and moves the air-jack 19towards the unlocking tool (FIG. 13). Forward movement of the air-jackafter it engages the tail of the unlocking tool will move the toolforwardly until the cam surfaces 108 enter between the release stubs 34of the unlocking levers 32 and the rail car deck. If the prong 47 issufficiently forward in socket 23 so that the locking plate 35 is freeto pivot, continued forward movement of the air-jack and unlocking toolwill cause stub 34 to ride up cam surface 108 and then along horizontalsurface 109 of the wedge so that the locking plate 35 will be pivotedfrom its upwards blocking position to its downward position wherein itwill allow prong 47 to be removed from the socket (FIG. 16). The jackpad 62 is raised to elevate the braked rear wheels of the automobile offof the deck and the automobile is then moved rearwardly to adjacent therail car door for removal.

If the automobile had shifted rearwardly during transit so that thelocking plate 35 is not free to pivot to unlocked position (FIG. 15)movement of the air-jack to its final position will cause wedges 105 totelescope towards the unlocking tool head 103 and against the bias ofsprings 107 after the unlocking wedges have engaged the lever stubs 34.The jack pad 62 will be raised to elevate the rear wheels of theautomobile and the automobile will be moved forwardly so that the prongs47 move forwardly in the sockets. When the prongs have so moved, springs107 will force the wedges 105 forwardly to cam stubs 34 upwardly andmove the locking plate 35 to the unlocked position of FIG. 16, therebyallowing the automobile to be moved rearwardly to the rail car door.

After an automobile has been removed from the rail car, the insideworkman removes the sockets 23 so the next automobile can be moved tothe rail car door and places the unlocking tool in position to releasethe next car.

Operations are repeated until the entire rail car is unloaded, and thecrew then moves to the next rail car to unload it.

Since all movement of the automobiles in the rail car is caused by theair-jack or forklift truck, the automobile engines are not needed untilafter the automobiles have been placed on the ground. As a consequence,there is no need to enter the automobiles when they are inside the railcar, there are no exhaust fumes in the rail car, and a dead battery orflat tire will not delay operations in the rail car.

The inside workman is always working in the space between the rear of acar and the rail car door and thus he never has to squeeze past the sideof automobiles in the rail car. As a consequence, damage to the side ofautomobiles is eliminated.

In addition to the numerous advantages previously set forth of sideloading as compared to end loading of automobiles, comparative timestudies show that the total manhours required to load automobiles into arail car by the side-loading method described herein is approximately75% of that required by presently used end-loading operations.

The forklift truck 80 is preferably constructed as shown in thecopending application of Benjamin F. Biaggini and Paul V. Garin, Ser.No. 646,941, filed Jan. 6, 1976, and entitled "LIFT TRUCK WITHATTACHMENT FOR CARRYING AUTOMOBILES", assigned to the assignee of thepresent application, and now U.S. Pat. No. 4,073,394 the disclosure ofwhich is incorporated herein by reference.

What is claimed is:
 1. Securement mechanism for releasably securing anautomobile to a horizontal rail car deck in response to longitudinalmovement of said automobile along said deck, said automobiles eachhaving a frame spring-suspended on wheels, said securement mechanismcomprising:a locking hook having a vertical shank and an elongated prongextending outwardly from the lower end of said shank, means forremovably attaching said locking hook to and beneath the frame of saidautomobile whereby longitudinal movement of said automobile along saidrail car deck will translate said prong along and above said deck, asocket member having spaced-apart top and bottom walls and spaced-apartside walls and open at at least one end for insertion of said prong intosaid socket, means for removably attaching said socket member to saidrail car deck with said open end of said socket in the path of movementof said prong, means forming a downwardly facing surface on said prongand means forming an upwardly facing surface on said socket member, saidsurfaces being interengageable upon insertion of said prong into saidsocket to limit upward movement of said prong relative to said socketwhen inserted thereinto, means forming a vertical surface on said shankand means forming a vertical surface on said socket, said verticalsurfaces being interengageable for limited movement of said prong intosaid socket, a lock member mounted on said socket member for movementbetween a first position blocking removal of said prong from said socketmember when said prong is inserted into said socket member and a secondposition allowing said prong to be inserted and removed from said socketmember, means biasing said lock member to its first position, meansforming interengageable surfaces on said lock member and said prong formoving said lock member to its second position by said prong as saidprong is inserted into said socket member.
 2. Securement mechanism asset forth in claim 1 and further including:means forming interengageablevertical surfaces on said locking hook and said socket member forlimiting sidewards movement of said locking hook relative to said socketmember when said prong is inserted into said socket member. 3.Securement mechanism as set forth in claim 1 and further including:meansforming interengageable cam surfaces on said prong and said socketmember for moving said locking hook downwardly relative to said socketmember during initial insertion of said prong into said socket. 4.Securement mechanism as set forth in claim 1 wherein said means forremovably attaching said socket member to said rail car deck comprisesmeans forming a slotted hole in said deck and a Tee-fastener on saidsocket member, said Tee-fastener having an elongated head passablethrough said slotted hole only when said head is aligned with the lengthof said slotted hole.
 5. Securement mechanism as set forth in claim 4and further including:means forming interengageable cam surfaces on saidprong and said socket member for moving said locking hook downwardlyrelative to said socket member during initial insertion of said pronginto said socket.
 6. Securement mechanism as set forth in claim 5 andfurther including:means forming interengageable vertical surfaces onsaid locking hook and said socket member for limiting sidewise movementof said locking hook relative to said socket member when said prong isinserted into said socket member.
 7. Securement mechanism as set forthin claim 1 wherein said socket member includes a horizontal shaftrotatably mounted in said side walls and wherein said lock member ismounted on said shaft for pivotal movement of said lock member betweenits first and second positions upon rotation of said shaft above itsaxis and wherein said means for biasing said lock member to its firstposition comprises a counterweight mounted on said shaft, saidcounterweight being movable downwardly by gravity to rotate said shaftand move said lock member to its first position.
 8. Securement mechanismas set forth in claim 7 wherein said counterweight has a release memberthereon spaced above said deck, said release member being movableupwardly relative to said deck to rotate said shaft to move said lockmember to its second position.
 9. Securement mechanism as set forth inclaim 8 and further including an unlocking tool comprising a bodyslidable along said deck and a wedge mounted on said body, and means forguiding forward sliding movement of said body along said deck to entersaid wedge between said deck and said release member.
 10. Securementmechanism as set forth in claim 9 and further including means mountingsaid wedge on the body of said unlocking tool for limited forward andrearward movement of said wedge relative to said body and spring meansbiasing said wedge forwardly relative to said body.